exporttask: make copy of project

Fixes #2037

app/task/export/export.cpp

@@ -28,10 +28,14 @@ namespace olive {
 ExportTask::ExportTask(ViewerOutput *viewer_node,
                        ColorManager* color_manager,
                        const EncodingParams& params) :
-  color_manager_(color_manager),
   params_(params)
 {
-  set_viewer(viewer_node);
+  // Create a copy of the project
+  copier_ = new ProjectCopier(this);
+  copier_->SetProject(viewer_node->project());
+
+  set_viewer(copier_->GetCopy(viewer_node));
+  color_manager_ = copier_->GetCopy(color_manager);
 
   // Adjust video params to have no divider
   VideoParams vp = viewer_node->GetVideoParams();

app/task/export/export.h

@@ -24,6 +24,7 @@
 #include "codec/encoder.h"
 #include "node/output/viewer/viewer.h"
 #include "render/colorprocessor.h"
+#include "render/projectcopier.h"
 #include "task/render/render.h"
 #include "task/task.h"
 
@@ -52,6 +53,8 @@ protected:
 private:
   bool WriteAudioLoop(const TimeRange &time, const SampleBuffer &samples);
 
+  ProjectCopier *copier_;
+
   QHash<rational, FramePtr> time_map_;
 
   QHash<TimeRange, SampleBuffer> audio_map_;